One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(4,8)(9,10,14,12)(11,13,16,15)(19,23)(21,24)(25,26)(27,33)(28,32)(29,30)(31,34)(35,40)(36,38)(37,39)(4,8)(6,7)(11,16)(13,15)(26,30)(27,34)(32,36)(35,37) involution — undirected(1,2,5,3)(4,6,8,7)(9,11,14,16)(10,15,12,13)(17,18,20,22)(19,21,23,24)(25,26)(27,31)(28,36)(29,30)(32,38)(33,34)(35,40)(37,39)(1,3,5,2)(4,7,8,6)(9,12,14,10)(11,13,16,15)(17,19)(18,21)(20,23)(22,24)(25,27)(26,31)(28,37)(29,34)(30,33)(32,40)(35,38)(36,39)(1,4)(2,6)(3,7)(5,8)(9,13)(10,11)(12,16)(14,15)(25,28,29,38)(26,32,30,36)(27,35,34,37)(31,39,33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.